Right temperature in winter and good growing conditions in the summer

Near the village of Turgutlu, Manisa, just 40 km east from Izmir, Genel Seracilik is running a big tomato operation, now existing of 17 ha of modern plastic greenhouses. The first 10 ha was built in 2006 and taken over by Genel two years ago from the previous owners. Last year another 7 ha block was built, making Genel an important player in the ever growing Turkish tomato world.

Like many areas in the western part of Turkey Turgutlu is blessed with hot water sources, which are used for the heating of the greenhouses. Genel uses a well, supplying water with a temperature of 80 °C, enough to maintain favourable conditions also during wintertime.

We had a talk with Bariş Dolaşir about the results of the first season of the new greenhouses, build in early 2012. The greenhouses are equipped with HARMONY 5045, a screen for both energysaving as well as shading. Special feature of this screen is its high degree of diffusity thanks to the application of special white strips. Aim for Genel was to be sure about the temperature in wintertime and at the same time maintain favourable growing conditions during summetime.

More light, no whitewashing
In comparision to the old greenhouse, the new greenhouse had a higher light level under HARMONY 5045. The old greenhouse had a conventional aluminum shade screen installed. Not only more light, but also more homogenious: no sun/shade pots in the greenhouse but uniform, diffused light. Both facts contributed to a steady and prosperous growth of the crop right after planting in September 2012. Bariş closes the screen for 50-70% when sun radiation is strong and temperatures are high. In this way he finished the crop successfully in June without any additional whitewashing. Quite an achievement in view of the sometimes extreme high temperatures, easily rising to levels of > 30 °C.

Additional insulation during wintertime
Winters in Turgutlu, Manisa are rather cold: average minimum temperature drops to 3 °C in December - February. At Genel they start closing the screens for 75% when the outside temperature drops below 8 °C; at lower temperatures the screen is closed further, always keeping a gap of at least 5%. This strategy leads to heating tubes of max 65 °C to keep the inside temperature at a level of 18 °C.

The future looks harmonious
For the planned future extension, Bariş would be happy when they will have a HARMONY screen again. Based on the experiences with the current 7 ha greenhouse block he prefers an open HARMONY shade screen. This makes a smaller screen gap and an even better cooling effect possible in summertime. For wintertime the open structure is expected not to lead to insufficient insulation.